Exam deck Flashcards
Properties of static electricity
Opposite charge repel, similar charge attract.
How friction cause insulators to become charged
When 2 insulators are rubbed against each other, electrons are transferred from one material to another. Objects that gain electrons become negatively charged and object that gain electrons become positive charged.
Double insulated appliance
It has outer casing made of plastic or insulating material. (Even when the liver wire touches the casing due to some faults, it won’t cause electric shock to users)
What cause crackling sound small spark
Excess charge escaping from the charged object.
Voltage
energy transferred per coulomb of charge
Power
energy transferred each second
Energy
total energy transfered in certain length of time (in seconds)
Factors that impact braking distance in certain length of time (in seconds)
speed of the car, braking force that can be applied, the friction between Tyres and road surface.
Momentum
Measure of how difficult it is to stop something that is moving.
Moment
Turning effect of a force about and hinge or pivot.
Thinking distance
Thinking distance is the distance a car travels after the driver has seen a danger but before the driver applies the brakes to stop (during this period the car is not decelerating.)
Braking distance
The braking distance is the distance travelled by the car after the driver has started braking and the car is
decelerating to rest.
Acceleration
rate object change its velocity
Velocity
speed in particular direction
Speed
distance travelled divided by time without regard to direction
